Sun Cobalt is preparing a major addition to its line of Linux-based server appliances this month despite the departure -- just weeks before the launch -- of the key executive who heads up the operation.

Stephen DeWitt, as president and chief executive of Cobalt, was instrumental in its growth and subsequent acquisition by Sun Microsystems in 2000. Latterly, DeWitt headed up the Cobalt division as vice president and general manager for content delivery and edge computing at Sun Microsystems. He left the company last Friday, four years after he joined Cobalt. One Sun Cobalt employee, in a posting to a discussion list on the Internet, noted that DeWitt's departure marked his four-year anniversary at the company, "when all his options vested."

DeWitt's departure was the only one of several high level bail-outs from Sun in past weeks that was not publicly announced. Sun president Ed Zander, who was also instrumental in the acquisition, is to retire from the company at the beginning of July after 15 years of service.

The upcoming launch, which the company has now confirmed is scheduled for mid-May, will significantly extend Sun Cobalt's line of Linux-based server appliances, ahead of a line of general purpose Linux servers due to ship later this summer.

Rumours of the new server appliances -- the first major launch under the Cobalt brand since Sun acquired the company in autumn 2000 -- have been circulating for several months. The company has still not released more details, but according to sources, is planning at least one dual-processor box, possibly called the Cobalt Raq550.

With the new server appliances, Sun Cobalt says it will eclipse IBM's recent entry into the market. "Our appliance product line is going to continue to improve," said group manager Bill Roth. "We have a couple of really cool product announcements coming out the second week of May."

Roth was keen to respond to the recent launch by IBM of its own server appliance line, for which IBM is using a Web interface supplied by Israeli software company Sphera. "The primary difference is that a lot of what they offer is shovelware," said Roth. "They have taken a lot of 'try and buy' software, and put it on the disk."

Cobalt marketing manager Pierre Reynes refuted suggestions that the IBM server appliance with Sphera software would be easier to set up for e-business applications than a Cobalt Raq. "The Raq 4 is now a fourth generation server appliance," he said. "We have designed it with a completely modular software architecture so customers can add their own management tools and develop their own management software." Reynes said the Cobalt Control Station, which can be used to manage dozens or even hundreds of Raqs, together with the company's solution centre, which provides links to third-party developer packages, would continue to make the Cobalt a compelling product.

See the Hardware News Sectionfor the latest update on everything from MP3 players and PDAs to supercomputing.

Have your say instantly, and see what others have said. Go to the ZDNet news forum.